The trust you build here is important because in times of crisis you can’t surge trust," said Lt. Gen. Stephen R. Lanza, referring to Yama Sakura 67, the joint, bi-lateral exercise with Japan that began and ended in early December.Lanza, who is the commander of I Corps, headquartered at Joint Base Lewis-McChord, Wash., spoke by telephone, from Camp Asaka, near Tokyo, where he and some 2,000 U.S. service members are training with more than 4,000 Japan Ground Self-Defense Force, or JGSDF, troops.The training, which has taken place every year since the early 1980s, is a simulation-driven, joint command-post exercise involving wide-area security and combined arms maneuver for decisive action.Yama Sakura is important, Lanza said, because it "reaffirms the strategic alliance between us, enhancing interoperability between our two forces, and, it builds a relationship necessary for the partnership we need to have in the future to prevent, shape and win."The prevent, shape and win strategy means soldiers are prepared to prevent conflict, shape the security environment and win wars, according to the new Army Operating Concept doctrine.This exercise features two joint force land component commanders operating against a well-entrenched threat, he said.The threat, Lanza explained, is "a near-peer competitor, involving a dispute on mineral rights to an off-shore island. The two headquarters are operating bi-laterally together to where existing systems and processes are working together to give the commander shared understanding to facilitate decision-making."A shared understanding is also important to "de-escalating conflict and avoiding miscalculation," he added.Lessons learnedBoth countries gain a lot from this exercise, Lanza said.The U.S. Army has gained a greater appreciation for how the JGSDF operates and fights – "very deliberate, very precise, understanding the impact of terrain and how synchronization and timing work for their combat multipliers in this type of environment," he said.Lt. Gen. Koichi Isobe, Lanza and their staffs, had some good discussions on transition from combat operations to civil control, he said."It’s probably the most detailed brief I’ve ever seen, very well thought out," Isobe said.Adding, "They brought a team down from their embassy and defense office with a good understanding both doctrinally, and with their laws."Isobe is commander of JGSDF’s Eastern Army, one of its five armies and the one participating in the exercise.In turn, Lanza said he believes that the JGSDF learned a lot from the Americans.The Japanese got an "appreciation of how to look at the threat and how to do predictive analysis on the threat," he said.They also learned how U.S. forces are adaptable and "how we maneuver and get commander’s latitude to make decentralized decisions based on intent."Predictive analysis involves future forecasting of events, trends and behaviors. It involves statistical modeling using vast quantities of information from databases. In this manner, deployment of forces and risk can be better assessed.Besides all that, the JGSDF gained "a greater appreciation for how we use our non-commissioned officers," he said, meaning that American NCOs have wide latitude of roles and responsibilities that Japan and most countries of the world assign to their officers.Command Sgt. Maj. James Norman, I Corps senior enlisted adviser, did "a very good job" talking with his Eastern Army counterpart about the role of the NCO, Lanza said.Adding, In "just the few days I’ve been here, I’ve seen a dramatic change in how their NCO corps has been used, and an appreciation of what the NCO Corps can do."Besides tactics and strategy, soldiers "are getting a better understanding and appreciation for Japanese culture," he added, meaning some time to get acquainted with the locals was built in with the training.As "we rebalance to the Pacific, these relationships will pay big dividends," he said.What’s next?In 2015, Yama Sakura 69 will be conducted with the Central Army. Besides the Central and Eastern Army, the JGSDF has the Northern Army, North Eastern Army and Western Army, for a total of five, each geographically based on Japan’s four main islands.Next year’s exercise will have "more joint play, a more robust joint task force headquarters, and the Japanese will likely provide different service components that add to the joint flavor of the fight, Lanza predicted.Also, there will be more amphibious operations than this year, more cyber play and more planning on transitions from military to civil operations, he added.Lanza concluded that the Japanese-American alliance is one of the most important there is, "economically, militarily and politically."Yama Sakura has done a lot to strengthen it.